Ballistoscope



Sept. 20, 1949. E. R. MANN ET AL BALLISTOSCOPE Filed May 13, 1944.

I INVENTORS "fl BYS Patented Sept. 20, 1949 UNITED STATES "-PA l 'E NT L -EFPEICE :ldALLISTOSCOBE Estle Ray Mann, Upper Montclair, 'ajlidsalmu'el 'wa'rd 'Stanton, Glen Ri'dge,"N. J. ,"a's's ignors*to Allen B. Du 'Mori't' Laboratories, I'n'c., Passaic,

,J.,::a,;corporation 'of'DelaWare i 1 ,ApplicationMayls, 1944, seria1'No.. s-5,4s4

'thedesired information or comparativequantities. Since the {magnitude of the initial co'nvolution of the spiral isa function of the impulse that is applie'dtb theinput terminal of the device, the spiral-is -used as a yisabl'e indication (if the desired information. V

-In' carryingcut- 'the invention an electrical pulse 'or-"charg'eis taken froma source and itseffect on 'a'dampe'd oscillator is observed by means of an 'oscillograph to examine the same. lior exam'ple, the pulse may 'be taken from acharged condenser to compareits capacity withthatof another condenser charged from the same source. Theffunctioningofthis'device is "somewhat liketha't of a ballistic galvanometer, the electrical properties thereof-being analogous to the mechanical prop- 'erties of a galvanometer.

The device comprises a, damped negative 'resistance; oscillator similar to a multivibrator that is provided with a resistance-capacitance tuned tank circuit andmeans for varying the "decre- "ment of'the-os-cillations. Two' twin Tresis'tancecapacitance circuitsare provided between the controlgrids'oi the oscillaton'a'nd the electrical characteristics of thetvvin T network aresuch that the impedance between the two grids i a maximumat ther'esonan't frequency of the-network.

The invention maybe"understoodfrom thedescription in connection -with the accompany drawwing Whichis a. diagram or connect-ions illustrating "the invention.

"Reference character I "indicates a terminal to which asignal 'or'impuls'e, suchl'as discharge from a charged condenser, for example, is to '-be apiplied. Thisiimpulse isicoupledby condenser' z 'to the grid of tube 3"which is indicated as a tetrode,

although other types of vacuum tubes may be used. A second tube ljwhich is the same sort of A source of positive voltage indicated by the plus sign 5 is connected through lo'ad resistors B and 1 to the plates of tubes 3 and 4, respec- 3 CIa'in IS. (015-315- 213) v r 2 Itiively. KresistorW'iis located between theso'urce Z5and'thescreenigrids ofLthe tubesl3 and l. "Resistors IlOTandJI-ar connectedfrom the cath' "odes'jofitub'es 3"an'd"f4 "toigroundtthrough a variable'resistor l'li'orll, which arefor fine control'of the damping of oscillations. Condensers l2' and I3 "are also connected respectively between the cathodes of these tubes'a'ndfground. 'The amount (if resistancejbetween cathodes'and ground'is con- "tro1ledby having 'thelead 1'4 between these're Qsistors connected byswitch. I toeither'one of.th e variable resistors I B'orfl;

switch i8 is providedforiconnecting thefplate fof tubefl3 by condenser l9and1ead20 toone'end 6f the resistor '2 I,"which is grounded at 1 the other end. A movab1e"contact .22 on resistor 2l1iis adapted to belconn'e'ct'e'd byis'witch"23 to the'controre'ridtof the tube :4. A switch is adapted to .corinect"the'p1ate iof-lthe tube A by condenser 26 i'andlea'd T2"! to one end of lthe resistor 128,'the tether endofthisrsistor'beinggrounded A movable contact on resi.s"tor"28 "is connected tofle'afd 29. This lead 29 maybe connected by'switch'30 ttowthe controlgrid o'f tubeflu V Theiswitches l'5, 18,23125 and 30 are 'ganged fto' m'ove together. .The connections; just described ia-re.for-controlHng-the feedback from the plates of Ltubes 3-and 4to the grids of eachother. The iswitch [Bin the'lefthan'd'position connects the plate of tube 3 byJcon'denserSZ and 1ead'33 to one end of'the'Jres'istor-M, the other end thereof'being grounded. The movable contact on resistor 34 -is connectedb switch-23,.in the leftrhand position, toithe grid of tube '4. t The switch'25 in its left hand position connects the .plate dftubefl"byicondenser 38 and lead 39 to one end o f 'theresistor 40, the other end off this resistor" being grounded. The movable contact 4| on resistor 40 can'be'con'nected by switch A "resistance-capacitance circuit consisting of tresistors' 48, "49359 andcondensers 5 l '52 and "53, provide hih-Qnircuits that are connected by leads '5! 'and il'a 'tothefeedback leads ZU and 21, respectively, when the switches' I B, '23, "25 and 3?] "are in their right' handpositions. 'Another re- 's istance capacitancecircuit consisting of resistors 58, 595 and condensers 6l, -62 "and as provide "high "Q circuits that rare connected -.by"1ea'ds '64 and 65 'tothe resistors 34 and 40 that =are conne'cte d"to the feedbak' leads 3-3 and. 39 when the 's'wit'chs $8, 23, 2'5 and 30 are in their left hand "pbs'itidfis. i i r Condensers 65 and 66 couple the outputs .from the tubes 3 and nto game-(antral resistor 61 and 68, respectively. slid iiig contactors 69 and-11),

which may be ganged when desired, connect these resistors 61 and 68 to duplicate phase shifting devices, only one of which needs to be described. Th adjustable contact 69 on resistor 61 is connected by lead H to the control grid of tube 12. The cathode of this tube is biased by resistor 14.

The resistance of resistor 80 which is the load resistor of tube 12 is the same as that of resistor 14. The plate of this tube may be coupled by switch 82 to a low frequency phase shifter con sisting of condenser 83 and resistor 84, or to a high frequency phase shifter consisting of condenser 85 and resistor 86. Both of these 'resistors.

are connected to ground through the cathode resister 14. Either one of these phase shifters may be coupled by switch 89 and slidable contacts 81 and 88 to any point on resistors 84-and 86.

The switch 89 is coupled by lead 90 and. condenser 9| to a balanced phase inverter deflection amplifier 92 of a known sortqrepresented diagrammatically, by which voltages aregenerated that are suitable forbeing applied by leads 93 and 94 to the defiection'plates 96 and ,91 of the cathode-ray tube 98 which is indicateddiagrammatically.

The elements of the other phase shifter which is connected to the tube 13, are designated by the same .reference characterswith primes that have been used indescribing thephase shifter above.

.The balanced phase inverter deflection amplifier I03 to which the lead 99' is coupled by condenser 9| provides deflection voltages ,for the horizontal deflection plates of the oscillograph tube 98. The

.leads I04 and I95 from the horizontal deflection amplifier I93 are connected to the horizontal. defiection plates I85, 181 as indicated. I The oscillographtube 98 may be any one of several known sorts. ,The heaterof this tube is indicated at ill), the cathode at l H, thefirst and second anodes at H2 and .ll3; these all being connected to suitable sources of potential in the usual way.

The operation is as follows: 7'

An impulse, for example, such as the discharge 7 from a condenserthat may have been charged under conditions to be investigated, isapplied to the terminal I, whereupon .damped oscillations are set up in the circuits of tubes 3 and 4. The

frequency of these oscillations depend upon which network 4853 or 58-63 is connected to the grids of tubes 3 and 4. The damping rate of the oscillations depend upon the adjustments of the variable resistors in the oscillator circuits and the positions of the switches, 18, 23, 2-5 and 39 and the positions of the contactors 22, 29,95 and 4| on resistors 2|, 28, 34 and .49, respectively.

Both the frequency and the damping can be varied over a wide range.

The trace of the cathode-ray beamon the face of the tube 98 can be made a spiral which spirals toward the center at a rate determined by the damping rate of the oscillations of tubes 3 and 4. The size of the spiral is controlled by the gain control contactors 69 and 'lo n resistors 61 and 88. The position of the switches 82 and 82' and the. positions of the contactors 81, 8'! on resistors 84, 84' and oontactors 88, 88' on resistors 86, 86' determine the amount ofphase shift of the signals applied to the vertical deflection plates 96, 91 and the horizontal deflection plates I86, I91, so that adjustments can be made to obtain spirals of the desired shape as well as the desired duration. r 1 a The sizes of the resistors and condensers indicated on'the drawing are illustrative. v

ances and capacitances connected respectively to the control grids of said tubes in a series parallel combination to ground, adjustable means for feeding back energy from the plate circuits of each of said tubes to the control grid circuits of the other tube in amounts sufficient to sustain dampedv oscillationsin said networks, means comprising adjustable resistors between the cathodes of said tubes andground to control damping of said oscillations, means for applying a pulse of voltage to one of the said control grids to initiate said damped oscillations, a stage of push-pull amplification to amplify said damped oscillations, means for controlling the amounts of voltage applied to the grids of said .push-pull amplifiers, and means for shifting the phases of the output signals from said push-pull amplifiers with respect to each other.

2. In combination, a pair of vacuum tubes not normally oscillating each comprising a cathode,

a control grid, a screen grid and an anode, resistance-capacitance networks comprising resistances and capacitances connected respectively to the control grids of said tubes in a series parallel combination to ground, adjustable means for feeding back energy from the plate circuits of each of said tubes to the control grid circuits of the other tube in amounts sufiicient to. sustain damped oscillations in said networks, means comprising adjustable resistors between the cathodes of said tubes and ground to control dampin of said oscillations, means for applying a pulse of voltage to one of the said control grids to initiate said damped oscillations, a stage of push-pull amplification to amplify said damped oscillations, means for controlling the amounts of voltage applied to the grids of said push-pull amplifiers, means for shifting the phases of the output signals from said push-pull amplifiers with respect to each other and means to amplify said phase shifted signals.

3. In combination, a pair of vacuum tubes not normally oscillating each comprising a cathode, a control grid, ascreen grid and an anode, resistance-capacitance networks comprising resistances and capacitances connected respectively to the control grids of said tubes in a series parallel combination to ground, adjustable means for feeding back energy from the plate circuits of each of said tubes to the control grid circuits of the other tube in amounts sufiicient to sustain damped oscillations in said networks, means comprising adjustable resistors between the cathodes of said tubes and ground to control damping of said oscillations. means for applying a pulse of voltage to one of the said control grids to initiate said damped oscillations, a stage of push-pull amplification to amplify said damped oscillations,

means for controlling the amounts of voltage applied to the grids of said push-pull amplifiers, means for shifting the phases of the output signals from said' push-pull amplifiers with respect (References on following page) Humby et a] Aug. 20, 1940 Name Date Geohegan Nov. 12, 1940 Diebold Dec. 17, 1940 Faudell Aug. 26, 1941 Lewis Dec. 9, 1941 Bartelink Jan. 1, 1946 Donaldson Oct. 1, 1946 FOREIGN PATENTS Country Date Great Britain Mar. 8, 1934 

